Red Line is Polyol "type" of ester oil.
Ref..
http://www.bobistheoilguy.com/esters-in-synthetic-lubricants/
Polyol esters can extend the high temperature operating range of a lubricant by as much as 50 – 100°C due to their superior stability and low volatility. They are also renowned for their film strength and increased lubricity which is useful in reducing energy consumption in many applications. The only downside of polyol esters compared to diesters is their higher price tag, generally 20 – 70+% higher on a wholesale basis.
The major application for polyol esters is jet engine lubricants where they have been used exclusively for more than 40 years. In this application, the oil is expected to flow at -65°C, pump readily at -40°C, and withstand sump temperature over 200°C with drain intervals measured in years. Only polyol esters have been found to satisfy this demanding application and incorporating even small amounts of diesters or PAOs will cause the lubricant to fail vital specifications.Polyol esters are also the ester of choice for blending with PAOs in passenger car motor oils. This change from lower cost diesters to polyols was driven primarily by the need for reduced fuel consumption and lower volatility in modern specifications. They are sometimes used in 2-cycle oils as well for the same reasons. In industrial markets polyol esters are used extensively in synthetic refrigeration lubricants due to their miscibility with non-chlorine refrigerants. They are also widely used in very high temperature operations such as industrial oven chains, tenter frames, stationary turbine engines, high temperature grease, fire resistant transformer coolants, fire resistant hydraulic fluids, and textile lubricants.
In general, polyol esters represent the highest performance level available for high temperature applications at a reasonable price. Although they cost more than many other types of synthetics, the benefits often combine to make this chemistry the most cost effective in severe environment applications. The primary benefits include extended life, higher temperature operation, reduced maintenance and downtime, lower energy consumption, reduced smoke and disposal, and biodegradability.
